6 Replies Latest reply on Mar 13, 2009 8:46 PM by Matt Wallace

# Constant helix angle tapered helix

Anyone got some ideas on how to create? I could brute force the math to create a table of points to create a curve through xyz points, but I would like to avoid that.
• ###### Constant helix angle tapered helix
Insert>Curve>Helix. Then select tapered helix...
• ###### Constant helix angle tapered helix
That gives constant pitch. I need constant helix angle. I can approximate constant helix angle by using variable pitch by brute force math to get a collection of points, but if I want to change the taper angle or helix angle, each individual point needs to be updated. I would like to avoid this and get SW to do the heavy lifting and not me- less chance of error.

I think my first response disappeared into the ether. If I end up with two responses, it reappeared.
• ###### Constant helix angle tapered helix
I'm having a real tough time wrapping my head around what the difference is between a constant pitch and a constant helix angle. I have attached another method of making a tapered helix. Maybe you can use that as inspiration to come up with a way to accomplish what you are looking for.

There used to be a description of it here, but it looks like the images got lost: http://solidmentor.com/modules...ck=AdvancedHelixShapes
• ###### Constant helix angle tapered helix
Charles,
If you think of the tapered helix wrapping around a cone sitting on the top plane, if its pitch stays constant then the tangent to the curve forms a greater and greater angle with the top plane as the diameter decreases. I believe this is what Matt is looking for.

• ###### Constant helix angle tapered helix
I mean, he's looking for that tangent angle with the top plane to stay constant.
• ###### Constant helix angle tapered helix
Charles

If you look at your part from the side, you can see how turn - to - turn spacing is constant (constant pitch). You can also see how steep the the angle to the center axis gets as the diameter gets small. It looks like a conical spring, which is sort of what I am after. But a spring made like this is very soft at the large diameter, while the small diameter is essentially non compliant. I need a lot more compliance at the small end and less at the large end- something that a constant helix angle, or something close, would go a long ways toward addressing. My part is going to be at a 60 deg included taper angle, and go from about 1/8 inch dia to 1-1/2 inch, so you can see the problem in the spring rate.

My first part was made using your technique, BTW, among others, and really beat this issue into me.